Digital broadcast systems that are currently available include ground wave digital television broadcast systems, digital satellite broadcast systems and mobile digital broadcast receiving systems.
FIG. 1 illustrates a digital broadcast receiver based on an MPEG-2 transport stream (TS). Referring to FIG. 1, the digital broadcast receiver comprises a code division multiplexing (CDM) unit 110, a CDM buffer 120, a demultiplexer 130, a demultiplexing buffer 140, a decoder 150, and an audio/video (audio/video) output unit 160.
Digital broadcast signals received in the CDM 110 are temporarily stored in the CDM buffer 120. Digital broadcast data output from the CDM buffer 120 is separated into various broadcast information and audio/video streams at the demultiplexer 130. The separated audio/video streams are stored in the demultiplexing buffer 140. Audio/video data output from the demultiplexing buffer 140 are decoded by the decoder 150 and outputted by the audio/video output unit 160. The audio/video output unit 160 includes a display device and an audio output device.
A variety of mobile broadcast receivers can receive digital broadcast content. Examples of such mobile broadcast systems are digital multimedia broadcast (DMB) terminals, digital video broadcast-handheld (DVB-H) terminals, and media flow terminals. Mobile broadcast receivers are formed by applying a broadcast reception function to personal portable terminals (such as cellular phones, personal digital assistants (PDAs), and terminals for a vehicle).
Some digital broadcast receivers may have storage means located inside or outside the receivers. For example, some digital broadcast receivers store digital broadcast content using a hard disk drive (HDD) as a storage device. Digital broadcast receivers which have storage devices can store digital broadcast content using large capacity storage mediums to reproduce and view the stored digital broadcast when needed.
Therefore, mobile broadcast receivers require a foundation which would allow the mobile broadcast receivers to receive and store digital broadcast in real-time using storage mediums and to reproduce and display the stored digital broadcast.
When mobile broadcast receivers store broadcast data received in real-time and, simultaneously, reproduce and display previously stored broadcast data using an HDD-based storage device, storage space is divided so that audio and/or video data are processed using either several files or one file.
Referring to FIG. 2, a storage space of a recordable storing medium is divided to store files (file 1, file 2, file 3, etc.) by a segment unit. When the storage space is filled with data during a recording process, the oldest data segment is deleted first. If a portion of the storage space that is assigned to an arbitrary file 1 is filled with audio and/or video data, file 1 is closed and another file 2 is opened to store audio and/or video data received afterward.
A noticeable time delay for opening or closing a file is generated when the reproduction and display of previously stored broadcast data simultaneously occurs with the storage of currently received broadcast data. Thus, when the receiving, storing and reproduction processes are simultaneously performed, delay or jitter is generated causing reduction of image quality.
Digital broadcast in an HDD-based storage device process only a single file at a time. Thus, only one file pointer is utilized during a write/read operation of audio/video data in order to both store and reproduce data in real-time. A single pointer is inadequate for the seamless reproduction of broadcast content. Systems and methods are needed that can overcome the above-noted shortcomings.